This application claims the priority of Korean Patent Application No. 2003-14482, filed on Mar. 7, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a novel conductive compound, an electrode coated with the compound, a sensor including the electrode, and a target molecule detection method using the sensor.
2. Description of the Related Art
There have been many studies on the development of biomolecule detecting sensors based on the electrochemical principles. One advantage of using the electrochemical principles lies in that sensors can be miniaturized. Accordingly, there have been great advances in research into electrochemical sensors, such as ionic sensors, gas sensors, biosensors, etc. In the fields of genomics and proteomics, it is very important to monitor information on the hybridization of DNA, among other biological molecules, and to monitor conformational changes of proteins. To this end, there have been developed sensors using electrochemically active organic substance and sensors using conductive polymers. In particular, intercalator-based sensors are ready to be released on the market as a result of extensive research thereon.
In conductive polymer sensors, only a few representative monomers capable of being polymerized on electrodes are available, and it is difficult to control the physical properties of polymers. As a result, research into the conductive polymer sensor has been relatively slow. Representative conductive polymer sensor materials include pyrroles, thiophenes, anilines, and the like. However, because anilines can only be used in acidic conditions, pyrroles and thiophenes have been the main focus of research.
However, pyrroles cannot be used for a long duration due to low redox potential (U.S. Pat. No. 6,201,086). Thiophenes have a higher redox potential but are more hydrophobic than pyrroles, so they are unsuitable for water-based biomolecule systems (Bauerle P. and Emge A., Adv. Materi., 3:324 (1998)).
Another problem arising with conductive polymer sensors lies in that the chain length of polypyrroles or polythiophenes cannot be controlled, disabling formation of an even, thin polymer layer. Therefore, such conductive polymer sensors are unsuitable for detecting trace of a target molecule, such as DNA, which is essentially dispersed. Moreover, due to the difficulty in controlling the chain length of the conductive polymers, signals generated as a result of a reaction between the target molecule and the conductive polymer layer are not reproducible.